Having seen what Katrina and other storms have done in the past year or so, Floridians began buying water and canned goods Tuesday after watching Wilma strengthen into a powerful hurricane.

Although the storm was not expected to approach Florida until the weekend, residents began stocking up early. Many said they take every storm seriously now, after witnessing the devastation from hurricanes that have ravaged the southern United States.

"People have learned their lesson and know better how to prepare. We're not waiting until the last minute anymore," said Andrea Yerger, 48, of Port Charlotte. She was buying material to protect her house, which had to be gutted because of extensive damage from Hurricane Charley last year.

Wilma became a Category 4 hurricane early Wednesday with top sustained winds of near 150 mph, according to the National Hurricane Center in Miami.

Wilma is expected to strengthen on a path that could threaten coastal areas such as Punta Gorda in southwestern Florida that were hit by Charley, a Category 4 storm that was the first of six hurricanes to strike the state since August 2004.

Computer models showed Wilma possibly making a sharp turn and bearing down on Florida over the weekend.

"When this storm makes the turn, it's going to start moving very quickly. So people need to get their supplies now. It's a good time to beat the rush," said Stacy Stewart, a hurricane specialist at the National Hurricane Center in Miami.

The state routinely replenishes emergency supplies of water, food and ice at staging points across Florida, so no additional action is needed, state emergency management spokesman Mike Stone said.

The six-month hurricane season will end Nov. 30. Wilma is the last on the 21-name list for storms this year. If any other storms form, letters from the Greek alphabet would be used for the first time, starting with Alpha.